Ophioglossum Linnaeus. Adder's-tongue.

Key to Ophioglossum

A genus of about 41 species, nearly cosmopolitan, primarily tropical. Circumscription of the genus follows PPG I (2016). Zhang & Zhang (2022) proposed splitting Ophioglossum into four genera, of which three are present in our region: Ophioglossum (sensu stricto), Haukia, and Whittieria. "Treating Goswamia, Haukia, and Whittieria at the rank of subgenus or section within Ophioglossum is an alternative which would not result in an unmanageable Ophioglossum in terms of species number or morphological circumscription. However, we find it convenient and informative to distinguish these three deeply diverged clades at the generic level because of their molecular, morphological, ecological, and biogeographical distinctiveness. It is also consistent across lineages in the family to recognize these meaningful units as genera." If Ophioglossum is separated, O. crotalophoroides is in genus Haukia, O. engelmannii in Whittieria, and other 4 species in Ophioglossum (sensu stricto).

ID notes: Ophioglossum is distinctly "unfernlike", with a single elliptical or ovate leaf blade (the trophophore) and a narrow, tonguelike sporangium-bearing sporophore branching from near the base of the trophophore blade. The sporophore bears the large sporangia in two rows. The netlike (interconnecting and anastomosing) venation requires strong backlight or chemical 'clearing' of the leaf to see well.

Ref: Lellinger (1985); Liu & Sahashi in FoC (2013); PPG I (2016); Wagner & Wagner (1993) In Flora of North America Editorial Committee (1993b); Wagner In Kramer & Green (1990); Wan, Zhang, & Zhang (2022); Zhang & Zhang (2022). Show full citations.

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